IBM Model F - repair cord options

[hokie1991]

Maybe this is a basic question but I have acquired this Model F as pictured - cord was cut at some point in its life.  It is very clean and seems in good condition but no real way to test it and it is not like replacement cables at at Best Buy... but I can find  an old keyboard extender and hack off one end then connect to the old board then have the original DIN connector... but I cant really test it.

Now it seem that these are pretty common:
https://www.ebay.com/itm/tinkerBOY-IBM-Model-F-XT-Model-M-AT-Keyboard-To-USB-Soarers-Converter/303710176869?hash=item46b6898665:g:h9AAAOSwB3VfdG7u

But it is a bit of an ugly solution.

So I am thinking maybe put a soarers board into the Model F and just have a corded USB connection.  Only issue is, I cant really test it until all the work is done.  Honeltly, I have have some skills but I am not a total expert here.

Any suggestions greatly appreciated.

[yui]

either way you will need a soarer or tmk converter to be able to test this keyboard as they do not use the good old ps/2 protocol, they predate it and only use a subset of it, so any "new" computer or normal converter expecting a proper ps/2 keyboard would not recognize it, otherwise it is just a midi 5 pole connector on the end, you can find pin-outs for the XT keyboard all over the internet to rewire it. as your cable is already cut either way i would just go for it and put the converter inside using what is left of the original cable, it is unlikely that the keyboard would be dead as those are incredibly reliable at any rate, and replacement controllers do exists although i am not sure that they are still built.

[nevin]

1. do you like the key feel? do you like the key layout? you can change the keymap.
2. how clean is the rest of the board? have you taken apart the entire board?
3. start with the converter (see what needs fixed)
4. if you like the layout and the key feel, do a full teardown, clean, replace anything that's broken/missing
5. if not put it up for sale. (at least you've learned a bit in the process)

[hokie1991]

Thanks for the advice,
Converter ordered
MIDI ordered - this is easiest way to check functionality I think

Step 2 will be an internal converter, good project for my 13 yr old... he just does not know it yet

It is interesting feel - I had a Model M in college 1987.. that I donated in the early 90's (still bugs me)
The board is a little dirty but not really, I am going to pull the keys and clean it up.
The foam seems very intact - so that is good. 

Guaranteed this will not end up in a donation somewhere, worst case it will end up with someone who appreciates it.

I am in the process of doing some work with a famous keyboard guy (dont know if you are allowed to reference other sites here) on resin analysis for the model M components. As it turns out in My career I have been basically a plastics engineer, and it is quite comical for me to have been reading about the "brittle plastic rivets" when in fact we are most likely looking and a combination of creep and fatigue on heat stakes which are famously bad for assembly - cheap but really terrible from a strength perspective - especially with unreinforced polymers.

And for my last rant... it is quite interesting to me to me that the rage is for a "bolt mod" which is along the lines of a 2' receiver hitch for a bike rack ( which I do actually)... just way over engineered.... a couple of well placed screws will basically completely unload the heat stakes and make any Model M rock solid - my opinion

Cheers and thanks for the input!
 

[nevin]

very interesting background. would love to see/hear your take on the restoration.

with your background... i'd love to chew your ear about retrobrite/abs yellowing

keep us posted on progress & feel free to ask if you get stuck.

[hokie1991]

Ok, now we are way off topic...  your questions were something else I was going to investigate.. the whole brominated FR yellowing topic... not all plastics have Br flame retardants, some do.  UV is the main culprit, it is tough on a lot organic materials, including people.  Plastics yellow, they can also can be easily stabilized with additives.  At the time when a lot of these parts were being manufactured, plastics industry was in a younger period than it is today, a lot was not known, and there was not 20 years of application history with components and resins.

Flame retardants add cost and kill mechanical properties - thats why they are not in everything... and also they are are terribly toxic.  What is worse for you, the smoke from burning plastic or the gasses generated by things we put in the plastics to keep them from burning.

UV stabilizers work, they are expensive... so they were not always put into cheap toys.  Not all plastics need UV stabilizers, some colors are more sensitive to UV as well, pigments can help with color stability.

I found this link - fear the man with 1 book.. but it adds some very dry wit that I have to admit I found hilarious..

https://www.quora.com/What-is-happening-in-terms-of-a-chemical-process-when-hydrogen-peroxide-is-used-to-restore-discoloured-Lego

Also, this guy speaks with a lot of chemistry knowledge and has a some experiments to back up his statements.

One of the reasons there are a lot of differences in how things yellow.. is that he parts that are made from "ABS" are remarkable NOT similar.  They can have different pigment systems, different stabilizer systems (or no UV stabilizers), could be PC/ABS, or a different plastic entirely.

I have used this to clean legos, it works quite well, I used it on the Model M keycaps as well, just gives them a nice "pop" and very non aggressive
https://www.target.com/p/oxiclean-powder-versatile-stain-remover-free-3-5lbs/-/A-51980122#lnk=sametab

Thanks

[nevin]

thanks. i didn't necessarily mean in this thread. just at another time. would like your thoughts.
i did a bunch of research on it as well, but it's only about half of a solution to the problem.
yes, i think we can de-yellow them to some extent (i just used peroxide) which worked pretty well for a short while. i think the next thing we need to look into is some kind of UV inhibitor that can be applied to the caps without it being a paint or something that will get tacky/break down with use because of oils in skin.

[hokie1991]

Well, guess what... There was a bad capacitor, 56uf 6V Sprague, it was a short which was smoking the whole setup.

So I found a pack of 10 kemet 56uf 6v capacitors on ebay (anyone need 9 extras?)   I probably could have used something cheaper but i just dont know that much abut electronics so I wanted to replace with teh same.

Plugged in the teensy converter and Wahooo!  works like it should.

Along the way I found another schematic which seemed to match exactly the keyboard, that helped me a lot confirming the short.

Next step is to clean it up a bit.

And for the humor... my 14 year old did the soldering and desoldering to remove and replace... then when we tried it and he started typing on it... he was comparing it to a model M... and was like wow dad this keyboard is way better LOL
Really thanks for all the input

[nevin]

glad you got it working. nice job.